Niki from Trulia here. If the listing is claimed to your profile, then it will match the information you have set in your profile, and making edits will correct the contact information.
However, if the listing is not claimed to you or your profile is not set up as a real estate professional, then the edits to the contact information must be done in the source site, and syndicated to Trulia.
Trulia is a host site, listing data is submitted from indexed agent or broker pages and reflected on our site the way it is sent.
Please feel free to contact us directly for help with your listing or profile at email@example.com or by calling 1-888-466-3501 Monday - Friday 7am to 4pm PST.